I'm not sure I completely understood your question, but I think this is the best way to answer it.

If you go all in preflop with 22 against AK you will win 52% of the time in the long run. It has nothing to do with whether Brunson thinks they beat AK or not, it's a fact.

However, when you're constructing preflop ranges, 22 is a hand that is very easily dominated by any pair, and in the best case scenario, you're flipping. Because of that, it's sometimes more profitable to add Qx to your range or Jx and avoid playing 22. 

Hope this helped.

This kind of thing started to make sense to me when I began examining and studying combinations. When you begin thinking of hands not just in terms of equity and outs, but also in terms of combinations, you see why a hand like AKo dominates a hand like 22 in the long run. 22 simply has a 52% equity heads up because it's already a made hand. The actual chances of it holding up through the flop, turn, and river though are definitely not 52%. 

There is a mountain of information on the subject of combinations and combinatorics in poker out there on the internet and the vast majority is free, accessible material. I'm by no means an expert on the subject yet but it's a regular, active part of my study and it's definitely maturing me as a poker player.